The Apalachicola River /æpəlætʃᵻˈkoʊlə/ is a river, approximately 112 mi (180 km) long in the State of Florida. This river's large watershed, known as the ACF River Basin for short, drains an area of approximately 19,500 square miles (50,505 km2) into the Gulf of Mexico. The distance to its farthest headstream in northeast Georgia is approximately 500 miles (800 km). Its name comes from the Apalachicola tribe, which used to live along the river. During Florida's British colonial period the river formed the boundary between East Florida and West Florida.